By Philip Pullella and Suleiman Al-Khalidi AMMAN (Reuters) - Pope Francis made an urgent appeal for an end to Syria's devastating civil war and an unscripted condemnation of the arms industry on Saturday at the start of his first trip to the Holy Land as pontiff. Speaking in Jordan, Francis repeatedly stressed the need to overcome differences and press for lasting peace in the Middle East. It was a message the Argentinian Pope delivered first in a speech at a royal palace, then to an open air mass, and finally and most forcefully at a church near the River Jordan where he pleaded for a political solution to Syria's "lacerating" conflict and an end to the arms trade which he said fuels war. "May all parties abandon the attempt to resolve issues by the use of arms and return to negotiations." More than 160,000 people have been killed in Syria's conflict and millions have fled to neighboring countries, including Jordan.